cherry pick: Version and release documentation (#531) (#604)

* .gitignore,Makefile: added 'build' Makefile target to build a binary within project context (in 'build' dir), and .gitignore clause

* Makefile: add mutiple build targets and reformat 'all' make target

* Makefile: added signature make targets to run under release target

* Makefile: ensure git and gpg are configured to have the same signing key

* doc/release-versioning.md: document supported k8s versions, architectures, and platforms in their own section

* release.sh,Makefile,pkg/generator/templates.go: check versions before tagging on release

pkg/scaffold/gopkgtoml.go

@@ -74,8 +74,8 @@ required = [
 [[constraint]]
   name = "github.com/operator-framework/operator-sdk"
   # The version rule is used for a specific release and the master branch for in between releases.
-  branch = "refactor/controller-runtime"
-  # version = "=v0.0.6"
+  branch = "refactor/controller-runtime" #osdk_branch_annotation
+  # version = "=v0.0.6" #osdk_version_annotation
 
 [prune]
   go-tests = true

pkg/scaffold/gopkgtoml_test.go

@@ -78,8 +78,8 @@ required = [
 [[constraint]]
   name = "github.com/operator-framework/operator-sdk"
   # The version rule is used for a specific release and the master branch for in between releases.
-  branch = "refactor/controller-runtime"
-  # version = "=v0.0.6"
+  branch = "refactor/controller-runtime" #osdk_branch_annotation
+  # version = "=v0.0.6" #osdk_version_annotation
 
 [prune]
   go-tests = true